Arrangement for a Vehicle

ABSTRACT

The invention relates to an arrangement (10) for a vehicle (1) for detecting an activation action for activating a function on the vehicle (1), in particular for detecting an activation action in a front, side and/or rear region (1.7, 1.4, 1.2) of the vehicle (1) for activating an opening and/or unlocking of a lid (1.3, 1.6) on the vehicle (1), comprising:at least one sensor element (20) for sensing a change, in particular an approach by an activation means (3), in the surroundings of the sensor element (20),a controlling arrangement (100) which is electrically connected to the sensor element (20) to provide an electric sensor signal specific to a parameter of the sensor element (20), wherein the parameter in turn is specific to the sensed change in the surroundings,an evaluation arrangement (200) for repeatedly determining the parameter of the sensor element (20) by means of a transmission of the sensor signal to a storage arrangement (250) in order to perform the detection of the activation action,an evaluation filter arrangement (210) of the evaluation arrangement (200) for band-pass filtering and/or for transconductance conversion of the sensor signal for the transmission to the storage arrangement (250).

The present invention relates to an arrangement for a vehicle fordetecting an activation action for activating a function on the vehicle.Furthermore, the invention relates to a system and a method.

It is known from the prior art that by means of a sensor element, suchas a sensor electrode, a variable capacitance can be provided, which isspecific for changes in the surroundings of the sensor element. Thismakes it possible to sense changes in the surroundings capacitively. Invehicles, such capacitive sensing can be used to detect approachesand/or gestures and thus activate functions on the vehicle.

Capacitive sensing is often based on the fact that the sensor element isevaluated by means of charge transfer. However, the shifting of electriccharges can cause interfering emissions (interference effects of thesensor element on the surroundings). Furthermore, interfering influencesfrom the surroundings (immissions on the sensor) can affect the sensing.

In addition, further interfering influences on the sensing are known,e.g. interfering capacitive effects (parasitic capacities, capacitiveloads e.g. of the vehicle body, or similar).

It is therefore an object of the present invention to at least partiallyeliminate the disadvantages described above. In particular, it is anobject of the present invention to provide an improved capacitivesensing.

The preceding object is solved by an arrangement with the features ofthe independent device claim, a system with the features of theindependent system claim as well as by a method with the features of theindependent method claim. Further features and details of the inventionresult from the respective dependent claims, the description and thefigures. Features and details described in connection with thearrangement according to the invention are of course also valid inconnection with the system according to the invention as well as themethod according to the invention, and vice versa, so that with regardto the disclosure of the individual aspects of the invention referenceis or can always be made to each other.

The object is solved in particular by an arrangement for a vehicle fordetecting an activation action for the activation of a function on thevehicle.

In particular, it is intended that the activation action is performed ina front, side and/or rear region of the vehicle in order to initiate theactivation of the function in the form of an opening and/or unlocking ofa lid on the vehicle when the activation action is detected.

An arrangement according to the invention can comprise at least thefollowing components, which are connected in particular with a printedcircuit board of the arrangement:

-   -   at least one (in particular electrically conductive) sensor        element for sensing a change, in particular an approach by an        activation means, in the surroundings of the sensor element,    -   an (electronic) controlling arrangement which is electrically        connected to the sensor element to provide an electric sensor        signal specific to a parameter of the sensor element. In        particular, it is intended that the parameter in turn is        specific to the sensed change in the surroundings,    -   an (electronic) evaluation arrangement for repeatedly        determining the parameter of the sensor element by means of a        transmission of the sensor signal to a storage arrangement in        order to perform the detection of the activation action,    -   an evaluation filter arrangement of the evaluation arrangement        for band-pass filtering and/or for transconductance conversion        (i.e. in particular conversion of an electric voltage into a        corresponding electric current) of the sensor signal for the        transmission to the storage arrangement.

In this way, the sensor signal for charging the storage arrangement canbe provided so that the charge is specific to the parameter. This typeof sensor evaluation is particularly robust against interferinginfluences due to the band-pass filtering.

The transconductance conversion can also be designed as atransconductance amplification to convert an input voltage into a(possibly over-) proportional output current. The input voltage is e.g.the sensor signal as a voltage signal, which is available at the outputof a sensor controlling arrangement. The output current is e.g. thesensor signal converted by the evaluation filter arrangement, which istransmitted to the storage arrangement. The evaluation filterarrangement can comprise a transconductance operational amplifier oralternatively operate completely without operational amplifier. In thelatter case the transconductance amplification can be realized with theamplification factor of maximum 1 (i.e. without amplification). Theevaluation filter arrangement can comprise an impedance in series with avirtual zero point of the storage arrangement in order to transmit thesensor signal converted by the impedance as a current signal via thisseries connection to the storage arrangement. This allows a chargeaccumulation in the storage arrangement depending on the amplitude ofthe voltage signal.

It may be possible that an operational amplifier is provided, e.g. theevaluation filter arrangement and/or the sensor controlling arrangement,which forms an active band-pass filter with further elements (such as acapacitor and/or a resistor and/or an inductor).

It is also advantageous if the vehicle is designed as a motor vehicle,in particular as a hybrid vehicle or as an electric vehicle, preferablywith a high-voltage electrical system and/or an electric motor. It mayalso be possible for the vehicle to be designed as a fuel cell vehicleand/or a passenger car and/or a semi-autonomous or autonomous vehicle.Advantageously, the vehicle comprises a security system that enablesauthentication, e.g. by communication with an identification transmitter(ID transmitter). Depending on the communication and/or theauthentication at least one function of the vehicle can be activated. Ifthe authentication of the ID transmitter is necessary for this purpose,the function can be a security relevant function, such as unlocking thevehicle and/or enabling an engine start. Thus, the security system canalso be designed as a passive access system, which initiates theauthentication and/or the activation of the function without activemanual actuation of the ID transmitter when the ID transmitter isdetected approaching the vehicle. For this purpose, the security systemrepeatedly sends a wake-up signal which can be received by the IDtransmitter during the approach and then triggers the authentication.The function can also concern the activation of a vehicle lightingand/or the actuation (opening and/or closing) of a lid (e.g. front orrear or side lid or door). For example, the vehicle lighting isautomatically activated when the approach is detected and/or the lid isactuated when a gesture of a user is detected.

It is also conceivable that—for the activation of the function on thevehicle—an activation action is detected by an arrangement according tothe invention. In particular, this could be an activation action outsidethe vehicle (i.e. not inside the vehicle interior). In other words, thesurroundings of the sensor element in which the change is sensed can beoutside the vehicle. If the activation action is successfully detectedby the arrangement according to the invention, the function can betriggered and/or the authentication can be initiated by the arrangement(in particular by a controlling device). The activation action can bee.g. the approach and/or the gesture, which is carried out by means ofthe activation means. The activation means and/or the activation actioncan be detected advantageously even if the activation means is anon-electronic object (and thus not an ID transmitter). Instead, theactivation means can be a non-electric and/or non-metallic and/orbiological substance, such as a user's body part. Therefore, the use ofcapacitive sensing to detect the activation action is particularlyadvantageous as it does not require any special precautions to be takenat the activation means.

An arrangement according to the invention is advantageously designed asan electronic circuit (circuit arrangement) and comprises electroniccomponents which are at least partially arranged on a printed circuitboard and can be interconnected via electric conductor tracks. At leastone of these components can also be designed as an integrated circuit(such as a controlling device in the form of a microcontroller). Some ofthe components can also be SMD (Surface-Mounted-Device) components. Thesensor element can be electrically conductive, e.g. as a conductor trackor as a flat electrode on the printed circuit board, or it can beconnected to the printed circuit board via a supply line (like anelectric line). In the latter case the sensor element is e.g. part of acable (like a coaxial cable), a flat electrode or an elongatedconductor. The sensor element can also be regarded as a capacitiveantenna, since the sensor element provides a variable sensorcapacitance. Furthermore, the variable sensor capacitance can optionallybe provided by several sensor elements, which are operatedsimultaneously or alternately. The printed circuit board and/or thesensor element is e.g. integrated in a door handle or in a bumper. Thesensor element can be arranged in such a way that the arrangement of thesensor element defines a detection region for the activation action.

In an arrangement according to the invention, it is possible that thesensor element is designed as a sensor electrode in order to provide theparameter specific for the sensing as a variable capacitance (alsocalled sensor capacitance), wherein the change in capacitance can bespecific for the change in the surroundings of the sensor element. Inturn, at least one shield element can be used to shield a change in aregion of the surroundings to be shielded from the sensor element sothat this change does not significantly change the capacitance.

In addition, it may be provided that a control signal is used to controlthe sensor element and a sensor signal is used to evaluate the sensorelement. The sensor signal can be dependent on the control signal. Alsoa charge transfer at the sensor element can depend on the controlsignal, because e.g. an electric voltage at the sensor element followsthe control signal (or corresponds to the electric voltage of thecontrol signal).

It may be intended that the sensor signal and/or the charge transfers atthe sensor element essentially

-   -   comprise the same frequency (working frequency) as the control        signal, and/or    -   comprise the same signal form as the control signal, preferably        sinusoidal and/or a periodic oscillating form, and/or    -   comprise a frequency in a working frequency range, wherein the        frequency (working frequency) of the control signal also lies in        this working frequency range,    -   are in phase or with the same polarity, comprise the same DC        voltage and/or DC current offset (or DC offset),    -   comprise a reduced frequency spectrum, which is adapted by a        filter arrangement and/or an evaluation filter arrangement.

Furthermore, it is conceivable that the sensor signal is present asalternating current (or alternating voltage) at least after (or through)a filtering of an evaluation filter arrangement. A filtering by theevaluation filter arrangement can also be implemented as band-passfiltering. In contrast, filtering of the control signal, in particularby the filter arrangement, can be implemented as low-pass filtering inorder to maintain a direct voltage component in the control signal.

Furthermore, it may be possible that the evaluation filter arrangementis designed to perform a transconductance conversion of the sensorsignal as an alternative or in addition to the band-pass filtering. Inthe context of the invention, a transconductance conversion isunderstood to mean in particular that an electric voltage is convertedinto a proportional and preferably equal electric current. Functionallythis can correspond to the function of a transconductance amplifier, ifnecessary with an amplification factor (proportionality factor) ofmaximum 1. However, in contrast to the transconductance amplifier, theevaluation filter arrangement cannot comprise an operational amplifier,but can achieve the transconductance conversion by means of the complexresistor and in particular by the connection in series with the virtualzero point.

The frequency of the sensor signal (as a periodic signal) can bedependent on a working frequency, i.e. in particular the frequency ofthe control signal at the output of a filter arrangement of thecontrolling arrangement. It is advantageous to use a single workingfrequency for the entire arrangement according to the invention both forthe control and the evaluation, in particular capacitive sensorevaluation, of the sensor element in order to carry out the control andevaluation of the sensor element with a given working frequency range.

For this purpose, filtering is used in particular for the electriccontrol (by the filter arrangement) and for the evaluation (by anevaluation filter arrangement), wherein the filtering is adapted to theworking frequency (e.g. forms a low and/or band-pass for passing theworking frequency range). This allows an optimal evaluation regardingEMC (electromagnetic compatibility) conditions (for emissions) andinterfering influences (for immissions). Also, by generating the controlsignal and/or adjusting the signal form and/or frequency of the controlsignal, an emission of the sensor element and a susceptibility toimmissions can be adjusted very precisely. In order to be able to usethese adjusted features also for the sensor evaluation, the sensorsignal can also be adapted according to the control signal. The sensorsignal can be specific for the charge transfers and still shows theadjusted properties. For this purpose, e.g. a sensor controllingarrangement is used, which amplifies the control signal depending on thecharge transfers (and thus the sensor capacitance of the sensor element)and outputs it as the sensor signal. This is possible e.g. by using anoperational amplifier in the sensor controlling arrangement, whichcomprises a counter-coupling by means of a capacitor.

Preferably, the storage arrangement can be designed as an electronicintegrator, in particular to accumulate received charges. Preferablyseveral charge transfers after several charges and discharges of thesensor element can be used to charge the storage arrangement.

A further advantage can be achieved in the context of the invention ifthe controlling arrangement provides a control signal for an electriccontrol of the sensor element for initiating charge transfers at thesensor element by means of the control signal, wherein the evaluationfilter arrangement provides band-pass filtering with a center frequencyand bandwidth which are adapted to a frequency and in particular signalform of the control signal in order to suppress interfering effects,preferably interfering immissions on the arrangement from thesurroundings, during repeated determination and/or during thetransmission to the storage arrangement. In other words, the sensorevaluation can be adapted to the electric control of the sensor elementby using the evaluation filter arrangement. This allows a reduction ofinterference frequencies both in the control (with respect to emissions)and in the sensor evaluation (with respect to immissions).

Advantageously, it may be provided in the invention that a sensorcontrolling arrangement of the controlling arrangement is electricallyinterconnected to the sensor element in order to initiate chargetransfers between the sensor element and the sensor controllingarrangement and to provide the sensor signal on the basis of the chargetransfers, wherein the evaluation filter arrangement is electricallyinterconnected to the storage arrangement and to the sensor controllingarrangement in order to filter the sensor signal and transmit itfiltered to the storage arrangement. Thus, the evaluation can besignificantly improved and provided less susceptible to interference.

Preferably, it may be provided within the scope of the invention thatthe storage arrangement is serially interconnected to the evaluationfilter arrangement via an input. Furthermore, an input resistance (inparticular of a current input) of the storage arrangement can be so lowthat a virtual zero point is formed at the input, so that preferably thesensor signal filtered by the evaluation filter arrangement is presentat the input as an electric current signal, in particular with thesignal form and/or frequency, which comprises an electric voltage signalof the sensor element and/or a control signal. This has the advantagethat the same working frequency can be used for the sensor evaluation asit is used for the electric control. In addition, the sensor signal cancorrespond to the unfiltered sensor signal (the voltage signal) withregard to amplitude and/or the amplitude can be proportional to a sensorcapacitance of the sensor element. This enables a particularly reliableevaluation.

Optionally, the evaluation filter arrangement can be designed as apassive or active filter. This allows a simple and cost-effectiveconstruction.

Further, it is conceivable within the scope of the invention that theevaluation filter arrangement comprises a bandwidth in the range from100 kHz to 1 MHz, preferably 250 kHz to 450 kHz and/or a centerfrequency of essentially 333 kHz. Such a frequency range has proven tobe particularly advantageous for sensor evaluation. Alternatively, othercenter frequencies are conceivable, but the bandwidth should berelatively small.

It may be provided within the scope of the invention that thecontrolling arrangement comprises a filter arrangement, in particular anactive filter and/or a low-pass filter and/or a band-pass filter, inorder to provide an electric control signal for the electric control ofthe sensor element (in particular via a controlling path) filtered, inparticular low-pass filtered, and/or formed, so that preferably anemission of the sensor element is adapted by the filter arrangement.Thereby, a frequency can be passed through the filter which correspondsto a working frequency and in particular the (middle) frequency of thecontrol signal. The filtering of the evaluation filter arrangement canalso be adapted to this working frequency and thus pass the workingfrequency.

For example, it may be provided that the controlling arrangementcomprises a filter arrangement, in particular an active filter, whichconnects a signal generator arrangement via a controlling path to thesensor element in order to provide an electric control signal generatedby the signal generator arrangement at the controlling path filtered, inparticular low-pass filtered, and/or formed for the sensor element, andthereby provide it as a filtered electric signal, preferably asinusoidal signal. The controlling path may also be provided with asensor controlling arrangement which uses the control signal to initiatecharging and discharging of the sensor element. The charges anddischarges are thus carried out in dependence on the control signal, sothat in particular the charge transfers of the charge and discharge arecarried out periodically with the working frequency. Thus, the controlsignal not only enables the control of the charge transfers, but also anemission of the sensor element.

According to a further advantage, it can be provided that the evaluationfilter arrangement is provided in addition to a filter arrangement ofthe controlling arrangement in order to additionally filter immissionson the sensor element for the determination of the parameter, whereinpreferably the filter arrangement is designed to filter a control signalfor the sensor element and the evaluation filter arrangement is designedto filter the sensor signal for the storage arrangement. Thus, theoverall interference behavior of the sensor can be improved.

A further advantage may be obtained in the context of the invention ifthe sensor element is designed as a sensor electrode to provide theparameter specific to the sensing as a variable capacitance, wherein thechange of the capacitance is specific to the change in the surroundings,wherein the arrangement is adapted for the repeated determination to:

-   -   repeatedly initiate charge transfers by means of a control        signal between the sensor element and a sensor controlling        arrangement, and in response thereto    -   repeatedly initiate charge transfers by means of the sensor        signal between the sensor controlling arrangement and the        storage arrangement, in particular an integrator, of the        evaluation arrangement,

so that the electric charge stored by the storage arrangement isspecific to the change in the capacitance. This enables a particularlyreliable sensor evaluation. In particular, the provision of differentcharge transfers by the sensor controlling arrangement can cause a kindof “decoupling”, in particular a reduced load on the sensor elementand/or distortion of the control signal. For this purpose, the sensorcontrolling arrangement can use at least one amplifying element like anoperational amplifier.

Furthermore, it may be provided within the scope of the invention that acontrolling device is interconnected to the storage arrangement of theevaluation arrangement in order to evaluate an electric charge stored bythe storage arrangement for determining the parameter specific to thesensing, preferably by an analogue-digital conversion of a voltage atthe storage arrangement, preferably by an analogue-digital converter ofthe controlling device. In addition to or as an alternative to theanalogue-digital conversion, the evaluation can use other measuringmethods, if necessary, to obtain a measured value for the voltage thatis as accurate as possible.

Optionally it is conceivable that the arrangement is at least partiallyintegrated as a capacitive sensor arrangement in a bumper of the vehiclein order to monitor the rear region of the vehicle and in order to openthe tailgate (and/or front lid and/or sliding door on one side) of thevehicle as the function on the vehicle, in particular in order toinitiate an output of an opening signal and/or an authentication check.This enables a comfortable access to the vehicle.

It is also optionally conceivable that the arrangement is designed torepeatedly charge and discharge the sensor element by an electriccontrol of the sensor element, and to carry out charge transfers by thesensor signal to the storage arrangement depending on this chargingand/or discharging, wherein a controlling device, in particular at leastone microcontroller, is electrically connected to a signal generatorarrangement, in order to initiate the electric control at the signalgenerator arrangement, and/or is electrically connected to the storagearrangement, in order to evaluate, after a charge transfer, the amountof charge stored in the storage arrangement and/or accumulated afterseveral charge transfers, and to perform the detection on the basis ofthe evaluation, preferably in order to output an activation signal foractivating the function on the vehicle if the amount of charge exceeds alimiting value. This has the advantage that the controlling device canbe used to synchronize the control and sensor evaluation to make theevaluation particularly reliable.

Furthermore, within the scope of the invention it is optionally possiblethat a sensor controlling arrangement is electrically interconnected tothe sensor element in order to generate an electric voltage signal witha specific frequency and/or signal form, preferably sinusoidal form, atan output on the basis of a control signal and/or on the basis of chargetransfers at the sensor element, wherein the evaluation filterarrangement is designed to convert the voltage signal into an electriccurrent signal with substantially the same signal form and/or frequencyfor charge transfers to the storage arrangement, so that the sensorsignal is produced as the electric current signal (in particular by thetransconductance conversion), wherein preferably the signal form and/orfrequency of the voltage signal corresponds to the signal form and/orfrequency of the control signal. This has the advantage that a frequencyspectrum and thus the susceptibility to interference for frequenciesoutside the operating frequency can be reduced during the sensorevaluation. In addition, the current signal can be dependent on theparameter of the sensor element, thus enabling a reliable evaluation.

It may be provided within the scope of the invention that a rectifierarrangement is interconnected between the evaluation filter arrangementand the storage arrangement in order to forward only charge transfers bythe sensor signal in the direction of the storage arrangement to thestorage arrangement by repeated switching, and preferably only duringthis forwarding to connect a virtual zero point of the storagearrangement to the evaluation filter arrangement and in particular to acompensation arrangement, and preferably otherwise to connect theevaluation filter arrangement to a ground potential. In this way, a loadon the evaluation filter arrangement can be significantly reduced andthe sensor signal can be transmitted particularly reliably and unalteredin order to further reduce the susceptibility to interference.

The subject of the invention is also a system comprising:

-   -   an arrangement according to the invention,    -   a controlling device for outputting an activation signal in the        case of the detection of the activation action (by the        arrangement according to the invention, wherein the controlling        device is in signal technical connection with the arrangement        according to the invention for this purpose),    -   a control apparatus which is connected to the controlling device        (in particular in a signal technical manner) in order to perform        the function on the vehicle when the activation signal is        received.

Thus, the system according to the invention has the same advantages asthey have been described in detail with respect to an arrangementaccording to the invention.

Also subject of the invention is a method for a vehicle for detecting anactivation action for activating a function on the vehicle, inparticular in a front, side and/or rear region of the vehicle foractivating an opening and/or unlocking of a lid on the vehicle. A sensorelement is provided for sensing a change, in particular an approach byan activation means, in the surroundings of the sensor element.

Here it is intended that the following steps are carried out, preferablyone after the other in the specified or in any order, wherein the stepscan be carried out at least partially in parallel and/or synchronizedand/or repeated:

-   -   providing an electric sensor signal which is specific for a        parameter of the sensor element, wherein the parameter in turn        is specific for the sensed change in the surroundings,    -   performing a repeated determination of the parameter of the        sensor element by means of a transmission of the sensor signal        to a storage arrangement,    -   performing band-pass filtering and/or transconductance        conversion of the sensor signal for the transmission to the        storage arrangement.

Thus, the method according to the invention has the same advantages asthey have been described in detail with respect to an arrangementaccording to the invention. In addition, the method may be suitable foroperating an arrangement according to the invention.

Further advantages, features and details of the invention result fromthe following description in which, with reference to the figures,embodiments of the invention are described in detail. The featuresmentioned in the claims and in the description may be individually or inany combination essential to the invention. The figures show:

FIG. 1 a schematic view of a rear region of a vehicle with anarrangement according to the invention and a system according to theinvention,

FIG. 2 a schematic side view of a vehicle with an arrangement accordingto the invention and a system according to the invention,

FIG. 3 a schematic diagram of parts of an arrangement according to theinvention,

FIG. 4 a schematic diagram of parts of an arrangement according to theinvention,

FIG. 5 a schematic representation of parts of an arrangement or systemaccording to the invention,

FIG. 6 a schematic representation of parts of an arrangement or systemaccording to the invention, and

FIG. 7 a schematic representation for the visualization of a systemaccording to the invention.

In the following figures, the identical reference signs are used for thesame technical features even from different embodiments.

FIG. 1 shows a view of a rear region 1.2 of a vehicle 1 with a systemaccording to the invention. An arrangement 10 according to the inventionmay be integrated in a bumper 1.1 of the vehicle 1 to detect anactivation action by an activation means 3 (such as a leg 3) of a user 2in the region of the bumper 1.1. For this purpose, the arrangement 10comprises a sensor element 20, which can be e.g. an elongated and/orcable-formed electrode 20 or a plane electrode 20 (i.e. flat electrode)or a capacitive antenna. It is also possible that a cable, like acoaxial cable, is used to form the sensor element 20. A detection of theactivation action can cause a tailgate 1.3 of the vehicle 1 to open. Forthis purpose, the arrangement 10 can comprise a signal connection with acontrol apparatus 8 of the vehicle 1 in order to output an activationsignal to the control apparatus 8 via the signal connection, whichinitiates the opening of the tailgate 1.3. A prerequisite for theopening can be a successful authentication with an identificationtransmitter 5 if necessary. In the same way, a lid (in particular door1.6) in the front region 1.7 and/or in the side region 1.4 of thevehicle can be activated by an arrangement 10 according to theinvention, wherein the arrangement 10 is then integrated e.g. in thedoor handle 1.5 or also in the bumper 1.1 or at a side sill.

FIG. 2 schematically shows a vehicle 1 in a side view. The side region1.4 and/or the front region 1.7 of the vehicle 1 may alternatively or inaddition to the rear region 1.2 comprise an arrangement 10 according tothe invention. For example, the sensor element 20 in the side region 1.4is integrated into a door handle 1.5 of the vehicle in order to detectthe activation action in the region of the door handle 1.5. For example,an approach to the sensor element 20 can be detected as an activationaction by the arrangement 10 in the side region 1.4. This activationaction can comprise an engagement of an activation means 3 (like a hand)into a door handle recess of the door handle 1.5. The arrangement of thesensor element 20 in the front region 1.7 can again be provided in thebumper 1.1, e.g. to open a front lid when detecting the activationaction in the front region 1.7. Another possible function which can beactivated by an activation action can be the opening of sliding doors1.6 of the vehicle 1, e.g. by approaching a side sill of the vehicle.

Basically, the activation action can comprise an approach to the sensorelement 20 or a gesture or the like. In particular, for the detection ofgestures, at least one further sensor element 20′ can be provided inaddition to a single sensor element 20, and can be arranged adjacent tothe sensor element 20. This makes it possible to recognize a movement ofthe activation means by the different sensing of the sensor elements 20,20′. Likewise, a shield element 160 for shielding can be arrangedadjacent to the sensor element 20 and/or further sensor element 20′.FIG. 1 shows an example of this arrangement in the bumper 1.1.

FIG. 3 shows an inventive arrangement 10 for a vehicle 1 which is usedfor the detection of an activation action for the activation of afunction on the vehicle 1, in particular as described in FIGS. 1 and 2for the detection of the activation action in a front, side and/or rearregion 1.7, 1.4, 1.2 of the vehicle 1 for the activation of an openingand/or unlocking of a lid 1.3, 1.6, in particular door 1.6 on thevehicle 1.

The arrangement 10 according to the invention may comprise at least onesensor element 20 for sensing a change in the surroundings of the sensorelement 20. This change is e.g. caused by the activation action, e.g. anapproach by an activation means 3. The sensor element 20 can be designedas an electric conductor, such as an electrically conductive surface (inparticular when mounting the arrangement 10 in the door handle 1.5) oran elongated and possibly flat electrode (in particular when mounting inthe bumper 1.1).

The sensitivity of the sensor element 20 to changes in the surroundingsand thus to the activation action can be explained in a simplified way,for example, as follows. In relation to the surroundings and/or a groundpotential 21, the sensor element 20 can form a capacitance (in thefollowing also called sensor capacitance CS). By generating an electricpotential (by means of an electric control described in the following)at the sensor element 20 an electric field can be created in thesurroundings. The sensor capacitance CS is influenced by the change inthe surroundings and is therefore variable. In other words, the changein sensor capacitance CS correlates with the change in the surroundings,i.e. the presence of an activation action. An evaluation of the variablecapacitance CS can be done in particular by evaluating the amount ofcharge stored in the sensor element 20 and provide conclusions about thechange in the surroundings, and thus serve to detect the activationaction. Thus, in particular the execution of charge transfers from andto the sensor element 20 is suitable to provide a sensor signal based onthe charge transfers (like the transferred amount of charge and/or thecurrent and/or voltage to be sensed), which can be evaluated for thedetermination of the variable capacitance CS.

To perform the electric control, a controlling arrangement 100 (in thesense of a control arrangement 100) can be used. The controllingarrangement 100 can be electrically interconnected to the sensor element20 via a controlling path KP to provide (i.e. enable) the sensing. Bymeans of the electric control, e.g. a (forced) charging and dischargingof the sensor element 20 can be initiated via charge transfers in orderto allow capacitive sensing by means of this control of the sensorelement 20. The electric interconnection can be realized e.g. by meansof an electric connection via conductor tracks of a printed circuitboard. The arrangement 10 according to the invention can be arranged atleast partially on this circuit board as an electric circuit. The sensorelement 20 and/or the further sensor element 20′ and/or the at least oneshield element 160 can be electrically connected to the controllingarrangement 100 of the arrangement 10 via conductor tracks via anelectric terminal of the circuit board, or it can itself be designed asa conductor track. The sensing is provided, for example, by the factthat an electric potential is generated by the controlling arrangement100 at the sensor element 20 in order to charge the sensor element 20,thus enabling, for example, the evaluation of the variable capacitanceCS as described above. It can also be a changing potential, so that anelectric voltage is generated at the sensor element 20, e.g. as aperiodic and/or sinusoidal voltage. For the evaluation of the sensorelement 20 an evaluation arrangement 200 is provided, which carries outa repeated determination of at least one parameter of the sensor element20 specific for the sensing in order to carry out the detection of theactivation action. In the concretely described example the variablecapacitance CS is considered as this parameter.

In addition, it is possible that at least one shield element 160 isprovided, which is arranged adjacent (and thus in the effective range)to the sensor element 20 for shielding the sensor element 20. To enableshielding by the shield element 160, a shield controlling arrangement150 with a terminal 150.A for the shield element 160 is provided. Theshield controlling arrangement 150 can be electrically connected to thecontrolling path KP and thus also to the shield element 160 via a shieldcontrolling input 150.B to provide the (previously described) electriccontrol of the controlling arrangement 100 for the shield element 160.In other words, the shield controlling arrangement 150 can provide thesame electric control for the shield element 160 as is used for thesensor element 20. For this purpose, an electric output voltage at theoutput 150.A of the shield controlling arrangement 150, which iselectrically connected to the shield element 160, follows an inputvoltage at the input 150.B of the shield controlling arrangement 150,which in turn is electrically connected to the controlling path KP andthus is also interconnected to the sensor element 20. For the sensorelement 20 and for the shield element 160 an identical control signalcan be used in this way to adjust the potential at the sensor element 20and at the shield element 160 in the same way by means of the controlsignal.

A connection point on the controlling path KP can be used to connect theshield controlling arrangement 150 with the controlling path KP. Forthis purpose, different positions on the controlling path KP can beused, e.g. directly on the current path to sensor element 20 or betweena filter arrangement 140 and a sensor controlling arrangement 170. FIG.3 shows an example of two possible connection points of the shieldcontrolling input 150.6 with the shield controlling arrangement 150.When using the connection point at the terminal 170.0 of the sensorcontrolling arrangement 170, the control signal output by the filterarrangement 140 can be used to set the potential at the shield element160. When using the connection point directly on the current path to thesensor element 20, the (essentially) same potential is used to set thepotential on the shield element 160 as is applied to the sensor element20.

In order to adjust the electric control particularly reliably, and inparticular not to overload the components at the connection point (suchas the sensor element 20 or the controlling arrangement 100), the shieldcontrolling arrangement 150 can comprise an operational amplifier 150.1for the electric forced guidance of the shield element 160. This can beused to connect the controlling path KP to the shield element 160 andthus generate the output voltage (also called shield voltage) at theshield element 160 equal to the input voltage at the controlling pathKP. The input voltage corresponds to a control voltage which is specificand/or proportional to the voltage at the sensor element 20. Preferably,the shield controlling arrangement 150 can form a voltage follower sothat an electric potential at the shield element 160 follows theelectric potential at the controlling path KP and in particular at thesensor element 20. Accordingly, a direct counter-coupling of theoperational amplifier 150.1 can be provided to obtain an amplificationfactor of 1. In this case, the shield controlling input 150.6 can beelectrically connected (directly) to the positive (non-invertinghigh-impedance) input of the operational amplifier 150.1, so that theinput resistance of the shield controlling input 150.6 is very high inorder to load the voltage at the shield controlling input 150.6 onlyslightly. The shield element terminal 150.A, on the other hand, can beelectrically connected to the output of the operational amplifier 150.1and, due to the counter-coupling, possibly also to the inverting inputof the operational amplifier 150.1 (directly) in order to provide anoutput with low resistance compared to the input resistance.

Furthermore, FIG. 3 shows that the controlling arrangement 100 comprisesa signal generator arrangement 130, which is electrically interconnectedto the sensor element 20 for the electric control of the sensor element20 in order to repeatedly generate an electric signal for charging thesensor element 20. This electric signal, hereinafter also referred to asthe control signal, can be used for the described electric control, andcan thus be provided for the sensor element 20, possibly also for thefurther sensor element 20′, and in particular also for the at least oneshield element 160 for setting the electric potential and/or forelectric charging and discharging. This provision takes place, forexample, by transmitting the electric signal via at least a part of thecontrolling path KP to a sensor controlling arrangement 170 and/or to ashield controlling arrangement 150. The generation of the control signalby the signal generator arrangement 130 thus causes the control signal(possibly previously modified, in particular filtered) to be present atthe terminal 170.C. By means of the sensor controlling arrangement 170and/or the shield controlling arrangement 150, the sensor element 20,the further sensor element 20′ and/or the shield element 160 can becontrolled by the control signal. For this purpose, a charge transfer(charging and/or discharging) is initiated at the sensor element 20and/or the further sensor element 20′ and/or the shield element 160 bymeans of the control signal (and thus also the generation of an electricfield is initiated). The evaluation of the amount of the transferredcharge can enable an evaluation of the variable sensor capacitance CS.The time development of this charge transfer can be influenced by theforming of the electric signal. For this purpose, the signal generatorarrangement 130 comprises e.g. a digital-analogue converter 130.1, whichcan also be designed as part of a controlling device 300 like amicrocontroller. The signal generator arrangement 130 can also be partof the controlling device 300. It is also conceivable that the signalgenerator arrangement 130 is only partially integrated into thecontrolling device 300 and that, for example, the digital-analogueconverter 130.1 is designed separately. Thus, a certain signal form ofthe control signal can be determined very reliably and exactly. Thissignal form can be further formed and/or improved by subsequentfiltering, if necessary, so that the control signal then comprises, forexample, a sinusoidal form according to an operating frequency.Therefore, the controlling arrangement 100 can comprise a filterarrangement 140, in particular an active filter 140 e.g. a low passfilter. This can be connected downstream of the signal generatorarrangement 130 as shown in the illustration in order to output thecontrol signal for the electric control of the sensor element 20 via thecontrolling path KP filtered to the sensor controlling arrangement 170,in particular by low-pass filtering. In this way, the control signal canbe formed with a certain working frequency, so that preferably anemission of the sensor element 20 by the filter arrangement 140 isadapted. This is advantageous for implementing EMC (electromagneticcompatibility) requirements during operation of the arrangement 10. Inother words, the controlling arrangement 100 can comprise a filterarrangement 140, in particular an active filter 140, which connects thesignal generator arrangement 130 to the controlling path KP in order toprovide an electric signal generated by the signal generator arrangement130 at the controlling path KP filtered, in particular low-passfiltered, and/or formed, and thereby provide it as a filtered electricsignal, preferably a sinusoidal signal. The active filtering is therebypreferably enabled by an operational amplifier 140.1 and by filterelements 140.2 such as at least one capacitor and/or at least oneresistor and/or at least one coil.

The electric signal (control signal) at the controlling path KP and inparticular at the terminal 170.0 can now be output to the sensor element20 via further components such as the sensor controlling arrangement 170and via a switching element 180 (if necessary via a terminal 180.A). Inorder to interrupt the charge transfer to sensor element 20 and, e.g.,to charge at least one further sensor element 20′, the switching element180 can be opened and closed in a clocked fashion. The sensorcontrolling arrangement 170 can comprise an amplifier and/or a voltagefollower and/or a voltage multiplier to generate an electric potentialat the terminal 170.0 in the same way at the sensor element 20,preferably so that the electric potential at the sensor element 20follows the electric potential at the terminal 170.C. For this purpose,the sensor controlling arrangement 170 comprises e.g. an operationalamplifier 170.1 and/or at least one filter element 170.2, such as acapacitor 170.2. A further switching element 180 can be integrated e.g.in the path between the terminal 170.A and the further sensor element20′ and can be switched e.g. alternately with the switching element 180.

The sensor controlling arrangement 170 can comprise the operationalamplifier 170.1 as a transmission element 170.1, which is electricallyinterconnected to the signal generator arrangement 130 in order toinitiate repeated charge transfers at the sensor element 20 on the basisof the control signal (at the terminal 170.C). This enables at leastpartial charging and discharging of the sensor element 20, and thus anevaluation of the charge stored in the sensor element 20. For thispurpose, e.g. a quantity (number) of the transferred charges and/or acurrent intensity during the charge transfers can be evaluated. Thecharge quantity and/or current intensity is then specific for the sensorcapacitance CS, in particular for the change of the sensor capacitanceCS. For this evaluation of the sensor element 20, the sensor controllingarrangement 170 can further comprise the at least one filter element170.2 as an amplifying means 170.2, which is electrically interconnectedto the evaluation arrangement 200 (and also to the sensor element 20)and thus provides the sensor signal on the basis of the chargetransfers. The sensor signal is specific for the (e.g. proportional tothe) sensor capacitance CS. Specifically, the sensor signal is specificfor the current intensity of the electric current and/or a voltagepresent at the terminal 170.A and thus specific for the charge transferor the sensor capacitance CS.

In order to be able to draw conclusions about the sensor capacitance CSfrom the sensor signal, the amplifying means 170.2, as shown in FIG. 3,can be electrically interconnected to the sensor element 20 to providecharge transfers (i.e. an electric current flow) between the sensorelement 20 and the amplifying means 170.2. Furthermore, the amplifyingmeans 170.2 can electrically connect an output of the transmissionelement 170.1 to a (in particular inverting) first input of thetransmission element 170.1, so that the amplifying means 170.2 forms acounter-coupling for the transmission element 170.1. Thecounter-coupling enables the charge transfers to be controlled by thecontrol signal when the control signal is applied to the other (inparticular non-inverting) second input of the transfer element 170.1. Ifthe first input is directly connected to the terminal 170.A, as shown inFIG. 3, the sensor controlling arrangement 170 provides a voltagefollower for the sensor element 20, so that the voltage on the (inparticular low impedance) terminal 170.A follows the control signal onthe (in particular high impedance) terminal 170.C. This corresponds tothe control of the charge transfers at the terminal 170.A by the controlsignal, and thus to a (particularly low impedance) sensor supply. Thesensor signal, on the other hand, can be provided by means of thearrangement (amplifier arrangement) comprising the transmission element170.1 and the amplifying means 170.2, which can be an electronicamplifier.

Preferably, the transmission element 170.1 is designed as operationalamplifier 170.1. In contrast, the amplifying means 170.2 comprises atleast one or two filter element(s) 170.2, in which, however, a capacitorC (e.g. in comparison to a resistor R) may dominate. Thus, theconfiguration of the arrangement comprising the transmission element170.1 and the amplifying means 170.2 can also be regarded as anintegrated circuit. The capacitor C makes it possible to provide anelectronic amplifier by this arrangement, in which the sensor signal isgenerated in the form of an electric voltage proportional to the sensorcapacitance CS on the basis of the charge transfers. In other words, thesensor controlling arrangement 170 comprises the arrangement of thetransmission element 170.1 and the amplifying means 170.2 to provide thesensor signal with an amplification. This means that the sensor signalis dependent on, and preferably proportional to, a voltage U1 at a firstterminal 170.A of the sensor controlling arrangement 170 (or at thefirst input of the operational amplifier 170.1), amplified by anamplification factor. The amplification factor may be dependent on, andpreferably proportional to, a ratio of the sensor capacitance CS to thecapacitance Cmess of the capacitor C. The voltage U1 (the output signal)at the terminal 170.A may again substantially correspond to the controlsignal in the form of a voltage U0 at the terminal 170.0 by using thevoltage follower or direct counter-coupling. This results in thefollowing relation for the sensor signal, which can be present asvoltage U2 at the terminal 170.B of the sensor controlling arrangement170:

U2=U0*(1+CS/Cmess)

It can be seen that the sensor signal U2 is amplified depending on thevariable sensor capacitance CS and the capacitance Cmess, i.e. it isgenerated as amplified voltage U0. Consequently, the sensor signal canbe used to determine the sensor capacitance CS. In order to enable thedisplayed linearity between the sensor signal and the sensor capacitanceCS, the resistance R of the amplifying means 170.2 is selected as largeas possible compared to (1/(2*π*f0*CSmax)), where f0 is the operatingfrequency, i.e. in particular the (average) frequency of the controlsignal, and CSmax is the maximum value of the sensor capacitance CS. Ifnecessary, the capacitance Cmess can be selected identical to themaximum variable sensor capacitance. The setting of Cmess therefore alsoallows the setting of a dynamic range for the evaluation of the sensorelement 20. In addition, the arrangement of the transmission element170.1 and the amplifying means 170.2 in cooperation with the sensorcapacitance CS provides a filter behavior (in particular band-passbehavior), which can be adapted to the working frequency.

The maximum variable sensor capacitance is, for example, the maximumcapacitance (capacitance value) that the sensor capacitance CS can takeon during the activation action.

It is also conceivable that the amplifying means 170.2 comprises as atleast one filter element 140.2 a capacitor C and/or a resistor R,wherein the capacitor C (or the capacitance Cmess of the capacitor C)and/or the resistor R are adapted to a maximum variable sensorcapacitance. Preferably the capacitance Cmess of the capacitor C cancorrespond to the maximum variable sensor capacitance. The capacitor Ccan be designed for counter-coupling with the transmission element 170.1(in particular operational amplifier 170.1) of the sensor controllingarrangement 170, and thus preferably form a feedback capacitor C. Viathe capacitor C, the output of the transmission element 170.1 and, inparticular, the output 170.B, at which the sensor signal is applied, canbe fed back to an input of the transmission element 170.1. In addition,this input can be directly connected to the terminal 170.A, to which thesensor element 20 is connected (possibly via a switching element 180),and thus the output signal or an electric voltage of the sensor element20 is applied. In this way, the output signal can be generated via adirect counter-coupling according to the control signal (follow this).In addition, the control signal or the output signal can be amplified(with an amplification factor depending on the sensor capacitance)depending on the charge transfers at the sensor element 20 (initiated bythe output signal), and then be output as the amplified sensor signal atthe terminal 170.B.

For the evaluation of the parameter specific for the sensing and inparticular the variable sensor capacitance CS, the charge transfer fromthe sensor element 20 (or the further sensor element 20′) to the sensorcontrolling arrangement 170 is provided according to the aboveexplanations, in order to evaluate this charge transfer on the basis ofthe sensor signal by an evaluation arrangement 200. For repeateddetermination, a charge transfer from the sensor element 20 to thesensor controlling arrangement 170 is repeatedly performed in order tocharge a storage arrangement 250, preferably an integrator 250, of theevaluation arrangement 200, depending on the amount of the chargetransferred in this way. In other words, depending on, and preferablyproportional to, the sensor signal, the storage arrangement 250 ischarged. In this way, the electric charge stored by the storagearrangement 250 can be specific to the change in capacitance CS. Forthis purpose, the storage arrangement 250 can provide a storagecapacitance CL, for example, by means of a storage capacitor.

The controlling device 300 can be interconnected via a terminal 250.A tothe storage arrangement 250 of the evaluation arrangement 200 in orderto evaluate the electric charge stored by the storage arrangement 250for the determination of the parameter specific to the sensing. Thus, anevaluation signal specific to the parameter and/or the stored electriccharge is sensed and evaluated. The evaluation signal can, for example,be a voltage across a capacitor of the storage arrangement 250.

It can also be seen in FIG. 3 that the shield controlling arrangement150 and the sensor controlling arrangement 170 are electricallyinterconnected via the controlling path KP with the same signalgenerator arrangement 130 and the same filter arrangement 140. Thismeans that an electric signal (the control signal) generated by thesignal generator arrangement 130 and/or filtered by the filterarrangement 140 is used at the controlling path KP for the control bothof the sensor element 20 and the shield element 160, preferably with anessentially identical signal form of the signal, preferably an at leastapproximate sinusoidal form, so that an electric potential differencebetween the sensor element 20 and the shield element 160 duringoperation of the arrangement 10 is always minimized during the controland/or sensing.

The shield element 160 can be designed as an active shield element 160(so-called “active shield”) for active shielding of the sensor element20, so that by means of the shield controlling arrangement 150 anelectric potential at the shield element 160 is actively tracked to theelectric potential at the sensor element 20. This makes it possible toimprove the shielding of the sensor element 20 from the vehicle 1 andthus to reduce a load that exists between the sensor element 20 and thevehicle 1. This load usually leads to a relatively large part of theevaluation signal, which is evaluated by the controlling device 300. Thevariable part of the evaluation signal due to the variable sensorcapacitance CS is reduced and therefore difficult to evaluate. Toimprove the evaluation, a compensation arrangement 230 is optionallyused. Depending on the amplitude of the evaluation signal, for example,it diverts a part of the electric current from the storage arrangement250. The use of a shield element 160, which comprises the same potentialfor shielding as the sensor element 20, can further reduce the describeddifficulties in the evaluation.

The sensor element 20 can be repeatedly charged and discharged via thefirst terminal 170.A of the sensor controlling arrangement 170 by meansof the charge transfers. These repeated charges and discharges can becontrolled by the control signal (due to a periodically changing voltageamplitude of the control signal). Depending on the charge transfers, anelectric sensor signal can be output via the second terminal 170.6 ofthe sensor controlling arrangement 170. It is possible that an electricfiltering of the sensor signal is performed. Correspondingly, filteringfor the evaluation branch can be performed when the sensor signal istransmitted to the storage arrangement 250, which therefore has noinfluence on the electric signal of the electric control (at thecontrolling path KP) and thus on the charging of the sensor element 20.For this purpose, an evaluation filter arrangement 210 can be used toperform a filtering (such as a band-pass filtering) of the electricsensor signal. This enables the evaluation filter arrangement 210 tofilter out interfering immissions from the surroundings of the sensorelement 20. Thus, the evaluation filter arrangement 210 can provide anEMC filtering of immissions. For this purpose, the evaluation filterarrangement 210 comprises, for example, a complex resistor andadditional filter elements. It is conceivable that the described form(e.g. sinusoidal form) of the electric signal of the electric control atthe controlling path KP (i.e. the control signal) affects the electricvoltage of the signal. The voltage of the sensor signal at the terminal170.6 can comprise the same form, but possibly an amplified amplitude(proportional to the sensor capacitance CS). However, the evaluation maydepend on the charge transfer and thus the electric current during thetransmission of the sensor signal to the storage arrangement 250.Therefore, the evaluation filter arrangement 210 can comprise atransconductance converter to perform a transconductance conversion ofthe sensor signal at the terminal 170.B. Such a transconductanceconversion means that a voltage is converted into a proportionalcurrent. In other words, the evaluation filter arrangement 210 can bedesigned for this purpose and/or interconnected in the evaluationarrangement 200 in such a way that an electric current with this form isformed at the output 210.A of the evaluation filter arrangement 210 fromthe voltage of the electric signal (sensor signal) at the secondterminal 170.B with the described form (e.g. sinusoidal form). Thetransconductance converter is designed e.g. as a transconductanceamplifier (using an operational amplifier), but preferably provides thetransconductance conversion without operational amplifier due to theinterconnection with the storage arrangement 250. This is made possible,for example, by the circuit configuration of the evaluation filterarrangement 210 in series with the storage arrangement 250. Furthermore,the downstream components 220, 250 can be of low impedance and/or thestorage arrangement 250 can comprise e.g. at the input 250.B theinverting input (−) of an amplifying element, and in particular of anoperational amplifier. The amplifying element of the storage arrangement250 can be designed so that countermeasures can be initiated immediatelyif a voltage occurs at the input 250.B. For this purpose, an operationalamplifier can regulate the differential voltage of its inputs to zero bymeans of a feedback. These precautions and/or the arrangement of theevaluation arrangement 200 serial to the storage arrangement 250comprise the effect that almost no voltage drops at the input 250.B oroutput 210.A. In other words, there is almost a ground potential at thispoint (at the input 250.B or at the output 210.A, if they are connectedto each other e.g. via a switch of the rectifier arrangement 220), sothat this point can be regarded as a virtual zero point.

The block 220 shown in FIG. 3 may involve one or more rectifiers, andthus a rectifier arrangement 220. The rectifier arrangement 220 may bewithout diodes or the like, so that there is essentially no (or almostno) voltage drop across the rectifier arrangement 220. This can berealized e.g. by using at least one electronic switch, which is clocked.In this way, a virtual zero point for the input 250.B or output 210.Acan be provided (when the switch is closed) by the rectifier arrangement220 and in particular by the at least one switch when establishing theelectric connection of the output 210.A with the input 250.B. If,however, the at least one switch is opened, the output 210.A of theevaluation filter arrangement 210 can be connected to a ground potential21. E.g. the switch connects the output 210.A with the ground potential21 as a changing switch. In this way, at least approximately one groundpotential can always be applied to the output 210.A, independent of theswitch position of the at least one switch of the rectifier arrangement220. This reduces the load on the evaluation filter arrangement 210considerably.

The described rectification can be a “coherent” rectification by the atleast one rectifier. This means that the at least one rectifier passesthe electric signal (sensor signal) from the evaluation filterarrangement 210 to the storage arrangement 250, preferablyphase-synchronized with the electric control. This causes the sensorsignal to be rectified coherently to the control signal. For thispurpose, each of the rectifiers can comprise at least one electronicswitch. The clock can be set in such a way that only positive (oralternatively negative) half waves of a given fundamental or harmonic ofthe electric signal (e.g. with the first harmonic as the fundamental ofthe frequency, which is passed by the evaluation filter arrangement 210as center frequency, and possibly further harmonics) are passed on.Therefore, the respective clock can be synchronized with the signalgenerator arrangement 130 to be adapted to the form of the electricsignal (control signal) of the electric control. Taking into account thefiltering by the evaluation filter arrangement 210, the phase shiftbetween voltage (corresponding to the electric signal of the electriccontrol at the controlling path KP) and current (corresponding to thesignal at the output 210.A of the evaluation filter arrangement 210) istaken into account in this synchronization. Furthermore, therectification can also be performed “incoherently” with diodes, ifnecessary.

It is also possible that rectification takes the form of one-wayrectification, or alternatively both the positive and negative halfwaves of the sensor signal can be used to transfer charge to the storagearrangement 250.

Furthermore, it may be provided that a frequency of the sensor signal(as a periodic signal) is dependent on an operating frequency, i.e. thefrequency of the control signal at the terminal 170.C (or at the outputof the filter arrangement 140). Thus, for the entire arrangement 10 asingle working frequency can be used for both the control and theevaluation of the sensor element 20 in order to perform the control andevaluation of the sensor element 20 with a given working frequencyrange. For this purpose, a filtering is used for the electric control(by the filter arrangement 140) and for the evaluation (by theevaluation filter arrangement 210), wherein the filtering is adapted tothe working frequency (e.g. forms a low pass and/or band-pass forpassing the working frequency range). This allows an optimal evaluationregarding EMC conditions (for emissions) and interfering influences (forimmissions).

FIG. 5 shows a possible design of the arrangement 10 according to theinvention, if it is used with an elongated sensor element 20. Such adesign is used, for example, if the sensor element 20 is to be used in abumper 1.1 at a front or rear side of the vehicle 1. This makes itpossible to sense a movement of the activation means 3 underneath thebumper 1.1 as an activation action, as it is also illustrated in FIG. 6.In contrast to the design of the sensor element 20 as a conductor trackof a printed circuit board, as it can be useful for the arrangement inthe door handle 1.5 to provide a spatially rather limited detectionregion, a separate sensor element 20 is connected to the printed circuitboard for a larger detection region. For this purpose, e.g. a sensorelement terminal 180.A of the circuit board can be used, which providesan electric connection with the switching element 180. This in turn canprovide the electric connection via the sensor controlling arrangement170 and the controlling path KP as well as the filter arrangement 140 tothe signal generator arrangement 130 (for charging) or via theevaluation filter arrangement 210 and the rectifier arrangement 220 tothe storage arrangement 250 (for evaluation). The above-mentionedcomponents 170, 140, 130, 210, 220, 250 can also be arranged on thecircuit board.

The printed circuit board with the components, in other words thecontrolling arrangement 100 and/or the evaluation arrangement 200, canbe regarded as one common component, which will be referred to as sensorswitching arrangement 400 in the following. It is optionally possiblethat this sensor switching arrangement 400 is designed as anindividually manageable part that can be mounted on the vehicle. Inorder to mount the arrangement 10 according to the invention, the sensorswitching arrangement 400 can be electrically connected to the sensorelement 20 and, if necessary, to at least one further sensor element 20′via at least one sensor supply line 410. The at least one further sensorelement 20′ can be connected to the sensor switching arrangement 400 viaat least one further sensor supply line 410. Optionally, it is alsopossible that the sensor switching arrangement 400 is electricallyconnected to at least one shield element 160 or further shield elementvia a shield line 420, in particular shield supply line 420, or that theshield line 420 forms the shield element 160 (i.e. if necessary also afurther shield element).

As an exemplary design for the arrangement 10 according to theinvention, a coaxial cable 450 is shown schematically in FIG. 5, whoseouter conductor 450.2 is used as the sensor element 20. In other words,the shield 450.2 of the coaxial cable 450 forms the sensor element 20.For this purpose, the sensor supply line 410 can be electricallyconnected to the outer conductor 450.2 via the terminal 180.A of thesensor switching arrangement 400. The terminal 180.A thereby transmitsthe electric signal of the electric control, which is given by thesignal generator arrangement 130 and/or the filter arrangement 140 (i.e.generated and filtered if necessary) and can further be output by asensor controlling arrangement 170 at the terminal 180.A. In the sameway, a shield element terminal 150.A of the sensor switching arrangement400 can be used to connect a shield supply line 420 to a shield element160 (see FIG. 6) or the shield line 420 connected to the shield elementterminal 150.A can itself form the shield element 160 (or, if necessary,another shield element). In particular, in the latter case and as shownin FIG. 5, it may be useful to operate the shield element 160 as apassive shield element 160. The inner conductor 450.1 (i.e. the core) ofthe coaxial cable 450 may remain unconnected if necessary.

When operating as a passive shield element 160, the shield element 160is connected to a specified constant electric potential via the shieldelement terminal 150.A during operation (always or during chargingand/or discharging of the sensor element 20). The electric potential ofthe shield element 160 can correspond to a ground potential 21 or be adifferent potential. In contrast, when operating as an active shieldelement 160, the electric potential of the shield element 160 can beadjusted and varied depending on the electric potential of the sensorelement 20.

It is illustrated by an arrow in FIG. 5 that a twisting of the supplylines 410, 420 can be carried out for mounting the arrangement 10according to the invention on the vehicle 1. First of all, the shieldelement 160 can run parallel to the sensor supply line 410 in the formof a shield line 420 as an elongated shield electrode 160. The twistingcan be done, e.g., by twisting the sensor supply line 410 and the shieldline 420 against each other and winding them helically over each other.The twisted supply lines 410, 420 are highlighted with a dotted andcontinuous line. In this way, the sensitivity to externalelectromagnetic interferences can be reduced to the supply lines 410,420. For mounting, the sensor supply line 410 can then be electricallyconnected to the outer conductor 450.2 so that the outer conductor 450.2forms the sensor element 20. The shield line 420 as well as the core450.1 of the coaxial cable 450 may remain unconnected. Alternatively,the shield line 420 is electrically connected to the core 450.1. In thisconfiguration it is advantageous to use the shield element 160 aspassive shield element 160.

Alternatively, it is also useful to operate the shield element 160 orthe shield line 420 as active shield element 160. For this purpose, adifferent interconnection on the coaxial cable 450 is selected ifnecessary. The sensor supply line 410 can be electrically connected tothe core 450.1 (i.e. the inner conductor 450.1) of the coaxial cable 450so that the core 450.1 serves as sensor supply line. The shield line420, in this case possibly as shield supply line 420, can beelectrically connected with the outer conductor 450.2 (i.e. with theshield) of the coaxial cable 450 so that the outer conductor 450.2 formsthe active shield element 160. The coaxial cable 450 with the core 450.1can be used as a supply line to the sensor element 20, which is thenseparate from the coaxial cable 450. The outer conductor 450.2, as theactive shield element 160, provides improved shielding of the sensorsupply line 410. The supply line 410, 420 to the coaxial cable 450 canbe twisted as described above, or they can be parallel lines.

A separate sensor element 20, which is connected e.g. via the twistedsupply lines 410, 420 described above and/or via the coaxial cable 450with the outer conductor 450.2 as active shield element 160 and/or via avariant deviating from this, to the sensor switching arrangement 400, isshown as an example in FIG. 6. The sensor element 20 can, for example,be designed as an electrically conductive surface (so-called flatelectrode 20) and/or as an electrically conductive line or similar. Thesensor element 20 is shown in a mounted arrangement (e.g. in the rearregion) near other parts of the vehicle 1. Schematically indicated is apart of the vehicle 1 which can be considered as ground potential 21.The vehicle 1 can cause a load on the sensor element 20 which can becounteracted by a shield. The electric field which can occur between ashield element 160 and the sensor element 20 (and which can be reducedor eliminated by operating the shield element 160 as an active shieldelement 160) and which serves for the sensing of the activation actionor the activation means 3 is indicated by arrows.

The form of the (active) shield element 160 shown here is particularlyadvantageous. The form is e.g. a U-form, wherein the two opposite sideparts 160.2 of the shield element 160 shield a side region and a centralpart 160.1 of the shield element 160 the central region or the vehicleside. In this way the detection region can be defined very precisely bythe open region 160.3 of the shield element 160 between the side parts160.2. The shield element 160 can be operated as an active shieldelement 160 e.g. by electrically connecting it to the shield (supply)line 420 or to an outer conductor 450.2 of the coaxial cable 450 (ifused as supply line). Furthermore, the sensor element 20 can beelectrically connected to the sensor supply line 410 and/or to the core450.1 of the coaxial cable 450 (if this is used as supply line).Alternatively, the form can be different from a U-form, in particular ifthe shield element 160 is wider than the sensor element 20.

FIG. 4 shows an evaluation filter arrangement 210, a rectifierarrangement 220 and a storage arrangement 250 with further details. Theevaluation filter arrangement 210 may comprise several filter elements210.1 for filtering the sensor signal, which is preferably provided as avoltage signal by the sensor controlling arrangement 170. These filterelements can each be designed as resistor, coil and/or capacitor, forexample, and thus be designed as RC and/or RLC and/or RL element. By theinterconnection and design of the filter elements 210.1, a low and highpass behavior of the evaluation filter arrangement 210 can be set, andthus a band-pass filter can be provided. This band-pass filter isadvantageously adapted to a frequency of the electric control, inparticular an operating frequency of the control signal, with regard toits passband and/or center frequency. By serial interconnection with avirtual zero point 250.B of the storage arrangement 250, the filteredsensor signal can then be transferred as a current signal to the storagearrangement 250. The current signal can comprise a current intensitywhich corresponds to the voltage signal with respect to amplitude and/orsignal form. In this way, a charge transfer to and thus charging of thestorage arrangement 250 can take place.

In order to enable charge transfer only in the direction of the storagearrangement 250, a rectifier arrangement 220 can be interconnectedbetween the evaluation filter arrangement 210 and the storagearrangement 250. In this case it is desirable that only certain halfwaves of the sensor signal are transmitted to the storage arrangement250 in order to cause only a charging of the storage arrangement 250 butno discharge by the sensor signal. For this purpose, the rectifierarrangement 220 can comprise at least one controllable rectifier 220.1,preferably in the form of a synchronous rectifier or the like, whichcarries out the rectification of the sensor signal synchronously, inparticular coherently, to the control signal. It is therefore necessarythat the signal form of the sensor signal (in particular the filteredsensor signal and thus the current signal) is known. It is takenadvantage of the fact that the sensor signal is generated by the sensorcontrolling arrangement 170 on the basis of the control signal, and thuscorresponds to the signal form of the control signal (the amplificationcompared to the control signal may, however, depend on the sensorcapacitance CS). To enable synchronization, the rectifier arrangement220, in particular the at least one rectifier 220.1, can therefore becontrolled by the controlling device 300. The controlling device 300 canin turn control the signal generator arrangement 130 to generate thecontrol signal so that the controlling device 300 knows the signal form.In this way, the rectification of the sensor signal is “coherent”.

Furthermore, FIG. 4 shows that the rectifier arrangement 220 cancomprise several rectifiers 220.1, preferably half wave rectifiers orfull wave rectifiers, which are connected to the controlling arrangement100 and/or controlling device 300. As an example, a first rectifier220.1 a, a second rectifier 220.1 b and a third rectifier 220.1 c areshown. These serve to be controlled by the controlling device 300 atdifferent frequencies, in particular clocked and/or coherent and/orsynchronized to the electric control signal, in such a way that one220.1 a of the rectifiers 220.1 transmits only a half oscillation of afundamental oscillation, in particular first harmonic, of the electricsensor signal to the storage arrangement 250, and the at least onefurther rectifier 220.1 b, 220.1 c suppresses the transmission, inparticular of this half oscillation, of further harmonics of theelectric sensor signal to the storage arrangement 250. The at least onefurther rectifier 220.1 b, 220.1 c can also, if necessary, permit thetransmission of the other half oscillation of the further harmonic ofthe electric sensor signal to the storage arrangement 250. Thisprinciple is further illustrated in FIG. 7. Here, the rectification 504is represented by the rectifier arrangement 220 in which the firstrectifier 220.1 a only switches at the negative half wave according tothe fundamental wave (see switching sequence 505) and the secondrectifier 220.1 b only switches at the positive half wave according toanother harmonic (e.g. 3rd harmonic) (see switching sequence 506). Inthis way, a rectified transmission of the sensor signal according to thefundamental oscillation with simultaneous suppression of interferingfrequency components according to the harmonics can be achieved.

Furthermore, it is shown in FIG. 4 that the rectifier arrangement 220comprises at least one electronic switch 220.2. In particular, theindividual rectifiers 220.1 can each be designed as or comprise a switch220.2. The at least one switch 220.2 (FIG. 4 shows three switches 220.2)can be connected to the controlling device 300 via a control path 220.3in order to electrically connect the storage arrangement 250 with thetransmission arrangement 170, 210 for the transmission of the electricsensor signal for certain half oscillations, in particular negative halfoscillations, of the electric control signal. For this purpose, acontrol signal of control path 220.3 for switching the respective switch220.2 can be synchronized with the electric control signal. The controlsignal can be output e.g. by the controlling device 300.

FIG. 7 schematically visualizes a method for the vehicle 1 for thedetection of an activation action for the activation of a function atthe vehicle 1. According to a first method step 501, an electric sensorsignal is provided which is specific for a parameter of the sensorelement 20, wherein the parameter in turn is specific for the sensedchange in the surroundings. Furthermore, according to a second methodstep 502, the parameter of the sensor element 20 is repeatedlydetermined by means of a transmission of the sensor signal to a storagearrangement 250. In addition, according to a third method step 503, aband-pass filtering and/or transconductance conversion of the sensorsignal for the transmission to the storage arrangement 250 is carriedout.

The above explanation of the embodiments describes the present inventionexclusively in the context of examples. Of course individual features ofthe embodiments can be freely combined with each other, if technicallyreasonable, without leaving the scope of the present invention.

LIST OF REFERENCE SIGNS

1 vehicle

1.1 bumper

1.2 rear region

1.3 tailgate

1.4 side region

1.5 door handle

1.6 door

1.7 front region

2 user

3 activation means

5 identification transmitter

8 control apparatus

10 arrangement

20 sensor element, sensor electrode

20 further sensor element

21 ground potential

100 controlling arrangement

130 signal generator arrangement, signal generator

130.1 digital-analogue-converter

140 filter arrangement, active filter, sinusoidal filter

140.1 operational amplifier

140.2 filter element

150 shield controlling arrangement

150.A shield element terminal

150.1 operational amplifier

160 shield element

160.1 central part

160.2 side part, leg

160.3 detection region, open region

170 sensor controlling arrangement, voltage follower

170.A first terminal of 170

170.B evaluation path, second terminal of 170

170.1 operational amplifier

170.2 filter element

180 switching element

180.A output of 180, sensor element terminal

200 evaluation arrangement

210 evaluation filter arrangement

210.A first terminal or output of 210

220 rectifier arrangement

230 compensation arrangement

250 storage arrangement, integrator

250.A first terminal

250.B second terminal, input

300 controlling device, microcontroller

400 sensor switching arrangement

410 sensor supply line

420 shield supply line

450 coaxial cable

450.1 inner conductor, core

450.2 outer conductor

501 first method step

502 second method step

503 third method step

CL storage capacitance

CS sensor capacitance

KP controlling path

1-18. (canceled)
 19. An arrangement for a vehicle for detecting anactivation action for activating a function on the vehicle comprising:at least one sensor element for sensing a change in the surroundings ofthe sensor element, a controlling arrangement which is electricallyconnected to the sensor element to provide an electric sensor signalspecific to a parameter of the sensor element, wherein the parameter inturn is specific to the sensed change in the surroundings, an evaluationarrangement for repeatedly determining the parameter of the sensorelement by means of a transmission of the sensor signal to a storagearrangement in order to perform the detection of the activation action,an evaluation filter arrangement of the evaluation arrangement at leastfor band-pass filtering or for transconductance conversion of the sensorsignal for the transmission to the storage arrangement.
 20. Thearrangement according to claim 19, wherein the controlling arrangementprovides a control signal for an electric control of the sensor elementfor initiating charge transfers at the sensor element by means of thecontrol signal, wherein the evaluation filter arrangement providesband-pass filtering with a center frequency and bandwidth which isadapted to a frequency of the control signal in order to suppressinterfering effects.
 21. The arrangement according to claim 19, whereina sensor controlling arrangement of the controlling arrangement iselectrically interconnected to the sensor element in order to initiatecharge transfers between the sensor element and the sensor controllingarrangement and to provide the sensor signal on the basis of the chargetransfers, wherein the evaluation filter arrangement is electricallyinterconnected to the storage arrangement and to the sensor controllingarrangement in order to filter the sensor signal and transmit itfiltered to the storage arrangement.
 22. The arrangement according toclaim 19, wherein the storage arrangement is serially interconnected tothe evaluation filter arrangement via an input, and an input resistanceof the storage arrangement is so low that a virtual zero point is formedat the input.
 23. The arrangement according to claim 19, wherein theevaluation filter arrangement is designed as a passive or active filter.24. The arrangement according to claim 19, wherein the evaluation filterarrangement comprises a bandwidth in the range from 100 kHz to 1 MHz.25. The arrangement according to claim 19, wherein the controllingarrangement comprises a filter arrangement in order to provide anelectric control signal for the electric control of the sensor elementat least filtered or formed.
 26. The arrangement according to claim 19,wherein the controlling arrangement comprises a filter arrangement whichconnects a signal generator arrangement via a controlling path to thesensor element in order to provide an electric control signal generatedby the signal generator arrangement at the controlling path at leastfiltered or formed for the sensor element, and thereby provide it as afiltered electric signal.
 27. The arrangement according to claim 19,wherein the evaluation filter arrangement is provided in addition to afilter arrangement of the controlling arrangement in order toadditionally filter immissions on the sensor element for thedetermination of the parameter.
 28. The arrangement according to claim19, wherein the sensor element is designed as a sensor electrode toprovide the parameter specific to the sensing as a variable capacitance,wherein the change of the capacitance is specific to the change in thesurroundings, wherein the arrangement is adapted for the repeateddetermination to: repeatedly initiate charge transfers by means of acontrol signal between the sensor element and a sensor controllingarrangement, and in response thereto repeatedly initiate chargetransfers by means of the sensor signal between the sensor controllingarrangement and the storage arrangement of the evaluation arrangement,so that the electric charge stored by the storage arrangement isspecific to the change in the capacitance.
 29. The arrangement accordingto claim 19, wherein a controlling device is interconnected to thestorage arrangement of the evaluation arrangement in order to evaluatean electric charge stored by the storage arrangement for determining theparameter specific to the sensing.
 30. The arrangement according toclaim 19, wherein the arrangement is at least partially integrated as acapacitive sensor arrangement in a bumper of the vehicle in order tomonitor the rear region of the vehicle, and in order to open thetailgate of the vehicle as the function on the vehicle.
 31. Thearrangement according to claim 19, wherein the arrangement is designedto repeatedly charge and discharge the sensor element by an electriccontrol of the sensor element, and to carry out charge transfers by thesensor signal to the storage arrangement depending on at least thischarging or discharging, wherein a controlling device is at leastelectrically connected to a signal generator arrangement, in order toinitiate the electric control at the signal generator arrangement or iselectrically connected to the storage arrangement in order to evaluate,after a charge transfer, the amount of charge at least stored in thestorage arrangement or accumulated after several charge transfers, andto perform the detection on the basis of the evaluation.
 32. Thearrangement according to claim 19, wherein a sensor controllingarrangement is electrically interconnected to the sensor element inorder to generate an electric voltage signal with at least a specificfrequency or signal form at an output at least on the basis of a controlsignal or on the basis of charge transfers at the sensor element,wherein the evaluation filter arrangement is designed to convert thevoltage signal into an electric current signal with at leastsubstantially the same signal form or frequency for charge transfers tothe storage arrangement, so that the sensor signal is produced as theelectric current signal by the transconductance conversion.
 33. Thearrangement according to claim 19, wherein a rectifier arrangement isinterconnected between the evaluation filter arrangement and the storagearrangement in order to forward only charge transfers by the sensorsignal in the direction of the storage arrangement to the storagearrangement by repeated switching.
 34. A system comprising: anarrangement according to claim 19, a controlling device for outputtingan activation signal in case of the detection of the activation action,a control apparatus which is connected to the controlling device inorder to perform the function on the vehicle when the activation signalis received.
 35. A method for a vehicle for detecting an activationaction for activating a function on the vehicle with a sensor elementfor sensing a change in the surroundings of the sensor element, whereinthe following steps are carried out: providing an electric sensor signalwhich is specific for a parameter of the sensor element, wherein theparameter in turn is specific for the sensed change in the surroundings,performing a repeated determination of the parameter of the sensorelement by means of a transmission of the sensor signal to a storagearrangement, performing at least band-pass filtering or transconductanceconversion of the sensor signal for the transmission to the storagearrangement.